Oh heck no on taking my own bed linens. I'm like Francesca on that. It either makes you appreciate what you've got at home or sends you out shopping for new bedding later. I do bring my pillow, a down and feather number, but I have issues in my neck and need it propped just so to sleep at all. And my teddy bear, TB, might go along on all road trips. cough. Or not.
I was thoroughly confused by how on earth you could get a flat double bed sheet to cover a king size bed. Then I remembered we don't really speak the same language across the board. Looked up UK vs. US bed sizes. Oh. Your King is our Queen. You couldn't do that here, you'd need a Queen flat sheet and it would cost the same as the King, so so close that it wouldn't be worth the effort.
I do buy the occasional clearance sale King sheet to turn into pillowcases. On sale I can get a sheet cheaper than a pair of standard cases. why....